As layered compounds which form a porous layered member, in general, there may be enumerated such intercalation substances as have been disclosed in, for example, Japanese Patent Application Laid-Open Publications Nos. 54-5884 and 54-16386, in which a foreign substance such as hydroxide or the like is intercalated for reaction between respective layers of a layered compound showing swelling characteristics. In these intercalation substances, however, there remains a problem that, in practice, the distance between the layers is so small as to be less than 10.ANG. so that the substances will be easily affected by adsorbed water and heat insulation properties at any satisfactory level cannot be achieved.
On the other hand, there have been disclosed in, for example, Japanese Patent Application Laid-Open Publications Nos. 60-131,878 and 60-137,812 porous layered members that are obtained by using a water-soluble high polymer and a finely porous smectite-type clay which are mixed to introduce polymer between clay layers, and then intercalating a cation is oxide or polymeric silica. In these porous layered members, the distance between the layers can be expanded to an extent of 30.ANG., but still there remains the problem that no sufficient distance for reducing or eliminating the influence of adsorbed water can be ensured between the layers.